Conventional motor-driven apparatus such as motor-driven chain saws have as standard equipment a lubricating-oil pump feeding lubricating oil from an oil tank to the moving saw chain.
Known motor-driven apparatus such as motor-driven chain saws where the saw chain moves around a guide bar are equipped with a lubricating-oil pump which in the operation of the chain saw continuously feeds lubricating oil for the chain links into a groove in the guide bar. Motor-driven apparatus of this type are also equipped with other attachments or tools, for example, with hedge trimmers, drills or the like which require no lubrication during operation. Further, it is known to equip motor-driven chain saws with sharpening devices which permit resharpening the cutting links with the motor running and the saw chain rotating.
When working with the known attachment tools which require no oil lubrication, it has been customary to drain the oil tank prior to mounting the attachment in order to avoid an unintentional oil leakage. For this purpose, the lubricating oil was collected in a suitable container to be saved for later use. In various applications the operator did not drain the oil tank so that oil continued to be fed without being needed; this resulted in additional oil consumption and environmental pollution. Also in other operations such as when the tool is being operated in the idle state, continuous lubrication of the tool is unnecessary.
In U.S. Pat. No. 2,070,203 there is disclosed a reciprocating oil pump in which the amount of oil pumped can be varied between a maximum delivery and a minimum delivery. As disclosed the piston in the pumping cylinder is provided with a pair of spaced cams rotatable with the piston. A sleeve providing a bearing for a portion of the piston is provided and has a cam pin secured to it for reciprocating the piston. The sleeve bearing is rotatably adjustable so as to change the relative circumferential position of the cam pin and cam surfaces to thereby change the quantity of oil pumped from a maximum delivery to a minimum delivery.
In U.S. Pat. No. 2,688,989 there is disclosed a lubricating device for chain saws in which the reciprocating pump is operable by an external plunger slidably mounted on the saw frame in a back position as to be engaged by the surface of log work piece which causes the piston to move inwardly against a spring means and thereby force oil under pressure through a conduit to the saw cutter links.
U.S. Pat. No. 4,636,147 discloses a lubricating-oil pump for a motor-driven apparatus which provides for interruption of the supply of lubricating oil to the tool driven by the motor. As disclosed, a control member is flattened on two opposite sides so that when turned in the inoperative position it does not contact the two control discs which effect axial stroke movement of the reciprocating piston with the result that the movement of the piston comes to a stop and oil flow is interrupted.
U.S. Pat. No. 4,644,658 discloses a lubricating-oil pump for a motor-driven apparatus having a work tool driven by the motor and interrupt means for interrupting the flow of lubricating oil to the work tool. The interruption of the oil supply is accomplished by blocking the upward stroke movement of the piston rod and pump diaphragm.
While such prior art devices provide improvement in the areas intended that is providing only an on/off regulation of the supply of oil, there still exists a great need to provide a lubricating-oil pump for motor-driven apparatus having a simple effective means for full range of the quantity of oil flow including reducing, increasing or stopping the quantity of oil flow as needed.
Accordingly, a principal desirable object of the invention is to provide a lubricating-oil pump system for motor-driven apparatus and the like with a state of control apparatus for regulating the quantity of oil flow from full maximum flow through a full intermediate range to a no flow or interrupted flow state.
Another desirable object of the present invention is to provide a lubricating-oil pump system which is positive and efficient in operation and which is readily and easily adjustable to regulate the quantity of oil flow.
Another desirable object of the present invention is to provide a lubricating-oil pump system of the above described objects which is compact, efficient, and of relatively inexpensive construction.
These and other desirable objects of the invention will in part appear hereinafter and will in part become apparent after consideration of the specification with reference to the accompanying drawings and the claims.